Laser additive manufacturing by selective laser sintering (SLS) or selective laser melting (SLM) of metal particles using commercial systems usually involves several steps, including: spreading a coating of a thin layer of metal powder over a metal surface to be built on; laser processing a preprogrammed pattern of a slice of the part to sinter or melt the powder, thereby adhering the slice to the underlying substrate; lowering of the part in the bed of metal powder; coating of another thin layer of metal powder over the previously processed surface; and repeating the laser processing, lowering, and coating steps until the component is additively built.
This process is typically conducted in a chamber filled with dry argon to protect the laser sinter/melt process from oxidation and to protect the powder from hydration. The lowering step is conducted using a vertical drive. The spreading step is conducted using a horizontal wiper mechanism. During both of these mechanical steps the laser processing halts.
A major limitation of this technology is a slow process speed. The laser can process a given layer relatively quickly, but the laser must be deactivated when the component is being lowered as well as when the component is being coated. The coating utilizes a relatively slow mechanical wiper in all known SLS/SLM equipment. Consequently, there remains room in the art for improvement.